Recombinant C-Terminal Domains from Scorpine-like Peptides Inhibit the Plasmodium berghei Ookinete Development In Vitro

Abstract

Malaria is a parasitic disease, caused by protozoa of the genus Plasmodium, and is transmitted to humans through the bites of infected Anopheles mosquitoes. More than 200 million cases of malaria are reported annually and about 400,000 deaths worldwide. Currently, the use of antimalarial drugs has been efficient in most cases, however, resistance to these drugs is increasing, making it necessary and essential to have a new range of possible drugs or medicines to combat this disease. Scorpion venom contains peptides whose functions are now intensively studied. Some of these peptides are known as Scorpine-like, which have anti-bacterial and antiplasmodial properties as they have been described to inhibit the development of parasites responsible for malaria. Scorpine-like peptides are composed of two structural domains: one α-helical N-terminal domain, and a C-terminal domain with the cysteine-stabilized α/β motif, which confers the peptide the function of blocking potassium channels and/or anti-bacteria activity. In this work, two C-terminal domains from Scorpine-like peptides were constructed and expressed in Escherichia coli, and their function was analyzed. We were able to demonstrate that the recombinant C-terminal domains rCterVm and rCterHg showed antiplasmodial activity producing 60% and 90% inhibition, respectively, of Plasmodium berghei development at 1 µM and 0.15 µM concentration, which makes these peptides promising candidates against Malaria.